---
id: config-options
title: Config Options
description: Config Options | Transloco Angular i18n
---

Below is a list of the `config` options and their usages:

### `reRenderOnLangChange`
Applications that don't allow the user to change the language in runtime (i.e., from a dropdown), should leave it `false`.
It can save on memory by rendering the view once and unsubscribing from the language changes event (defaults to `false`):

```ts
translocoConfig({
  reRenderOnLangChange: boolean
})
```

### `defaultLang`
Sets the default language: (defaults to `en`)
```ts
translocoConfig({
  defaultLang: 'en'
})
```

### `fallbackLang`
 Sets the default language/s to use as a fallback. See the `TranslocoFallbackStrategy` section if you need to customize it:
```ts
translocoConfig({
  fallbackLang: 'en',
  fallbackLang: ['en', 'ru']
})
```

### `failedRetries`
 How many time should Transloco retry to load translation files, in case of a load failure (defaults to 2):
```ts
translocoConfig({
  failedRetries: 1
})
```

### `prodMode`
 Whether the application runs in production mode: (defaults to `false`)  
 When enabled, Transloco will disable all console warnings.

```ts
import { environment } from '../environments/environment';

translocoConfig({
  prodMode: environment.production
})
```

### `availableLangs`
 The available languages in your application:
```ts
translocoConfig({
  availableLangs: ['en', 'es']
})
```

### `missingHandler.allowEmpty`
Whether to allow empty values: (defaults to `false`)
```ts
translocoConfig({
  missingHandler: {
    allowEmpty: true
  }
})
```

### `missingHandler.useFallbackTranslation`
Whether to use the fallback language for missing keys or values: (defaults to `false`)
```ts
translocoConfig({
  fallbackLang: 'en',
  missingHandler: {
    // It will use the first language set in the `fallbackLang` property
    useFallbackTranslation: true
  }
})
```

### `missingHandler.logMissingKey`
Whether to `console.warn` a missing key: (defaults to `true`)
```ts
translocoConfig({
  missingHandler: {
    logMissingKey: false
  }
})
```

### `flatten.aot`
Check the optimization plugin:
```ts
import { environment } from '../environments/environment';

translocoConfig({
  flatten: {
    aot: environment.production
  }
})
```

### `interpolation`
The start and end markings for parameters: (defaults to `['{{', '}}']`)
```ts
translocoConfig({
  // This will enable you to specify parameters as such: `"Hello <<<value>>>"` 
  interpolation: ['<<<', '>>>']
})
```    
